Rare tardigrade fossil found trapped in amber

Microscopic tardigrades can be found in almost any habitat on Earth (Credit: Ralph O. Schill / European Space Agency)

The tardigrades, or water bears, are virtually indestructible. The eight legs microscopic animals can resist extreme temperatures, survive without food for decades, and even exist in a empty in the space. But, although they have been around for over 500 million years, they rarely appear on the fossil record. Their miniature size and lack of hard tissue make them difficult to fossilize. Even when they get preserved, the tiny creatures are difficult to spot and often get neglected. Over the years, only two tardigrade fossils have been found. Now a third specimen – one of the new tardigrade species – joined this exclusive group.

“The discovery of a fossil tardigrade is really ageneration event “, Phil Barden, co-author of the October 6, 2021 study published in the Proceedings of the Royal Society B, said in a press release. “What is so remarkable is that tardigrades are a omnipresent old line who has seen everything on Earth, from the fall of dinosaurs to the rise of earthly colonization of plants. Yet they are like a ghost line for paleontologists, with almost no fossil save.”

The tardigrade has been preserved near the top of the amber surface. (Photo credit: Phillip Barden (Harvard / NJIT)

The 16-million-year-old specimen found shut in in amber in the Dominican Republic, is the first of its kind from the Cenozoic period – Earth current geological era, which began 66 million years ago. The previous fossils found – one in 1964 and the other in 2001 – date back 78 million years and 92 million years, respectively.

Better yet, the specimen is proximity on the surface of the amber allowed Barden and his team at the New Jersey Institute of Technology to examine the mouth and claws of the former tardigrade. They were also able rebuild what his throat and bowels looked like. The team called the new species Paradoryphoribius chronocaribbeus. “Chrono” means time in Greek, while “caribbeus” is a nod to the area of ​​the Dominican Republic where the fossil was found.

The tardigrade fossil seen under a microscope (Ninon Robin / Harvard / NJIT)

Researchers say the discovery was extremely fortunate, especially since Barden had initially picked up the amber to examine ants and beetles trapped inside. It was only after a observer a lab member noticed that the tardigrade was almost invisible, 0.6 millimeter long torso alongside the insects, that they turned their to concentrate away from insects. “It was luckier they saw it… because it’s not something they are looking for,” said study manager Marc Mapalo. The doctorate Harvard University candidate believes fossils like these will paleontologists to better understand how these creatures evolved and survived the five major masses of Earth extinction events.

Resources: Livescience.com, Businessinsider.com, NPR.com